While acyclovir helps millions fight viral infections, it's not for everyone. Understanding these important restrictions can prevent serious complications and ensure safe treatment.
Absolute "No-Go" Situations
Acyclovir should never be used in these cases:
- Known severe allergy - To acyclovir or valacyclovir components
- Certain genetic conditions - Like Lesch-Nyhan syndrome
- Specific drug combinations - With nephrotoxic medications in kidney patients
High-Risk Groups Requiring Special Caution
Patient Group |
Potential Risks |
Precautions Needed |
Severe kidney impairment |
Drug accumulation, toxicity |
Dose adjustment, frequent monitoring |
Elderly patients |
Increased side effects |
Lower starting doses |
Neurological disorders |
Seizure risk |
Close supervision |
Dehydrated patients |
Kidney damage |
IV fluids with IV acyclovir |
Dangerous Drug Combinations
Particularly risky interactions occur with:
- Other nephrotoxic drugs - Like aminoglycoside antibiotics
- Probenecid - Increases acyclovir blood levels dramatically
- Immunosuppressants - May require dose adjustments
- IV preparations - With other IV medications
Special Population Considerations
Pregnancy and Breastfeeding
While not absolutely contraindicated:
- Requires careful risk/benefit analysis
- Topical preferred when possible
- Breastfeeding generally safe but monitor infant
Pediatric Use
Special rules apply:
- Not for neonates without specialist oversight
- Dosing by weight critical
- Different formulations available
Red Flag Symptoms
Stop immediately and seek help if experiencing:
- Swelling of face/lips/tongue
- Severe skin reactions
- Unusual bleeding/bruising
- Extreme fatigue/confusion
For comprehensive safety information, review acyclovir contraindications with your healthcare provider.
When the Benefits Outweigh Risks
Doctors may still prescribe with caution when:
- Life-threatening infections exist
- No alternatives available
- Close monitoring possible
- Patient understands risks
Key Safety Takeaways
- Allergy history is crucial
- Kidney function must be considered
- Drug interactions matter
- Special populations need extra care
